CVE-2026-23986

MEDIUM EPSS 12.9%
Published Jan 21, 20265mo ago · Modified Jun 17, 20262w ago
6.9 CVSS 4.0
Medium
Find Similar
Published Jan 21, 2026 5mo ago
Last Modified Jun 17, 2026 2w ago

Description

Copier is a library and CLI app for rendering project templates. Prior to version 9.11.2, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the `--UNSAFE,--trust` flag. As it turns out, a safe template can currently write to arbitrary directories outside the destination path by using directory a symlink along with `_preserve_symlinks: true` and a generated directory structure whose rendered path is inside the symlinked directory. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. Version 9.11.2 patches the issue.

CVSS Details

Base Score
6.9
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Local
Attack Complexity Low
Privileges Required None
User Interaction P
Scope X

Threat Intelligence

EPSS Exploit Probability
12.9% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-61

Affected Products 1

VendorProductVersionRange
copier-orgcopier* <9.11.2

References 3

  • github.com https://github.com/copier-org/copier/commit/b3a7b3772d17cf0e7a4481978188c9f536c8d8f6
    Patch
  • github.com https://github.com/copier-org/copier/releases/tag/v9.11.2
    ProductRelease Notes
  • github.com https://github.com/copier-org/copier/security/advisories/GHSA-4fqp-r85r-hxqh
    ExploitThird Party Advisory

Remediation

  • github.com https://github.com/copier-org/copier/commit/b3a7b3772d17cf0e7a4481978188c9f536c8d8f6
    Patch